want to put a little cement ''bridge" across the front of my garage door to keep water out. Any suggestions on

Question

what type of cement to use, and how to prepare the floor?

Answer 1

Generally thin set concrete wont bond or hold up vey well when mounded up like you want to do.
Try replacing the rubber seal on the bottom of your garage door first.

Answer 2

If you really want to do this right, you will need to roughen an area of about 8-12" wide, centered on your garage door. Then, you need to chip down at least 1" on the outer edges, to about 3" in from the edges for the length of the opening. Brush out all loose material with a clean broom. Get some epoxy bonding agent at the hardware store and a cheap brush to apply it. Use a good non-shrink grout or concrete mix without aggregrate. Mix the grout or concrete so it is kind of stiff. Apply the bonding agent per manufacturer's instructions, then place the grout/concrete along the strip. Shape it with your trowel so it slopes to the center, leaving a flat center about 2" wide (for the garage door). Don't cross any joints (like the joint between the garage floor and the driveway).

Answer 3

I put a drain in front of my garage instead. Water was getting under my garage floor and erroding it away without our knowledge. Then on Superbowl Sunday the garage floor collapsed and broke my septic pipe that was under the garage floor, which caused a flood in my basement. Any water that comes down my driveway now enters the drain and is piped away underground. I live in CT and we get ground frost which causes cement to crack that's why I suggest this method instead. You can buy the drain sections at lowe's and Home Depot. They connect together with a grate on top of them. Works great.